In various types of implements, particularly in lawn mowers with rotary blades, there is concern with regard to mounting the engine on the implement housing and with regard to the bending of the engine crankshaft when the implement, such as the rotating blade, strikes an object. The prior art includes several constructions pertaining to this problem, such as having the rotating blade slip on its drive mounting when an object is impacted, and also radially supporting the extending end of the engine crankshaft, where it extends beyond the remainder of the engine, to thereby minimize radial bending of the crankshaft upon impact.
U.S. Pat. Nos. 3,890,773 and 4,738,089 are concerned with the problem of the bending of the engine crankshaft upon impact, and those patents therefore show arrangements whereby the crankshaft extending end is radially supported to minimize the bending. They also show arrangements, though different from the present invention, for mounting the engine onto the implement, and with the mounting member providing the radial support for the crankshaft extending end.
U.S. Pat. No. 4,205,737 shows only an engine mounting on a mower, and no bearing supports. U.S. Pat. No. 2,720,071 shows another example of an arrangement of a part, beyond the engine itself, which presents a rotation bearing which receives and rotatably supports the engine shaft. In that instance, the support member is on the mower housing which simply accommodates the entry of the shaft relative to the mower housing, and the support extends into the housing and provides the rotational bearing for that shaft extension. There is no separate part which attaches directly to the engine base or the like and which also presents the rotation support for the shaft extension, all in one unit which can then be mounted onto the implement itself, as in the present invention.
The present invention further distinguishes from the prior art in that it provides for a member which mounts directly to the engine base and which presents the shaft extension with a rotational support and which provides maximum radial strength against bending of the shaft extension upon impact. Further, the present invention provides for assembling the aforesaid engine and attached member with the implement itself so that a maximized sturdy assembly is provided and one which is of a universal nature to accommodate present-day commercial engines which are arranged for mounting on implements, such as rotary lawn mowers.
Still further, the aforementioned objects and advantages are achieved in an assembly wherein the rotating tool, such as the lawn mower blade, is frictionally driven by the engine shaft so that there will be nominal slipping upon impact. To achieve this, the friction drive parts are concentric and thereby permit close tolerances and promote the practicality of assembly of the parts.
Also, the arrangement for supporting the shaft against bending upon impact is such that the support is extended to the very limit of location adjacent the plane of rotation of the cutting blade itself, and thus there is only a minimal of extension beyond the support for a minimal of bending moment acting upon the shaft.
Other objects and advantages will be apparent upon reading the following description in light of the accompanying drawings.